Compositions and processes for downhole cementing operations

ABSTRACT

The present invention relates to methods of cementing, for example, an oil or gas well. The method may involve pumping a suspension of a filler mixture and at least about 5 weight percent of a thermosetting resin based on the total weight of resin and filler mixture. Advantages may include superior properties and reliability as compared to conventional cementing operations often involving Portland cement.

FIELD OF THE INVENTION

The instant invention pertains to, for example, novel compositions andprocesses for downhole cementing operations.

BACKGROUND AND SUMMARY OF THE INVENTION

As part of the wellbore construction process, a hole or wellbore istypically drilled into the earth and then often lined with a casing orliner. Usually sections of casing or liner are threaded together orotherwise connected as they are run into the wellbore to form what issometimes referred to as a “string.” Such casing may comprise a steeltubular “pipe” having an outer diameter that is smaller than the innerdiameter of the wellbore. Because of the differences in those diameters,an annular area occurs between the inner diameter of the wellbore andthe outer diameter of the casing. Absent the presence of anything else,wellbore fluids and earth formation fluids may migrate lengthwise alongthe wellbore in that annular area.

Wells are typically constructed in stages. Initially a hole is drilledin the earth to a depth at which earth cave-in or wellbore fluid controlbecome potential issues. At that point, drilling is stopped and casingis placed in the wellbore. While the casing may structurally preventcave-in, it will not prevent fluid migration along a length of the wellin the annulus. For that reason, the casing is typically cemented inplace. To accomplish that, a cement slurry is pumped down through thecasing and out the bottom of the casing. Drilling fluid, water, or othersuitable wellbore fluid is pumped behind the cement slurry in order todisplace the cement slurry into the annulus. Typically, drillable wiperplugs are used to separate the cement from the wellbore fluid in advanceof the cement volume and behind it. The cement is left to cure in theannulus thereby forming a barrier to fluid migration within the annulus.After the cement has cured, the cured cement remaining in the interiorof the casing is drilled out and the cement seal or barrier between thecasing and the formation is pressure tested. If the pressure test issuccessful, a drill bit is then run through the cemented casing anddrilling is commenced from the bottom of that casing. A new length ofhole is then drilled, cased, and cemented. Depending on the total lengthof well, several stages may be drilled and cased.

Unfortunately, the cements employed for the aforementioned operationsoften suffer from a variety of deficiencies. For example, the cementsmay not have sufficient strength, flexibility, or toughness to withstandthe pressures, corrosion, and other stresses that may often beencountered downhole. Failure of the cement may lead to disastrous andexpensive consequences to the well and/or the surrounding environment.Similarly, currently available cements may be cumbersome to process. Forexample, hexavalent chromium compounds and other particulates in thecement may require that special handling procedures are implemented soas to limit worker exposure to such hazardous materials. Accordingly,what is needed are new cement compositions and processes that solve oneor more of these deficiencies with conventional cement used in downholeoil and gas operations.

Advantageously, the instant invention reduces or eliminates one or moreof the mentioned deficiencies with the prior art cementing compositionsand processes. In one embodiment the invention involves a novel methodof cementing a well. The method comprises the step of pumping asuspension. The suspension comprises a filler mixture and at least about5 weight percent of a thermosetting resin based on the total weight ofresin and filler mixture. The suspension cures when subjected to acatalyst. The cured composition comprises one or more of the followingcharacteristics (a) through (g): (a) a tensile strength of at leastabout 300, 1000, 1500 psi according to ASTM C1273 with a 0.01 inch/minof cross-head speed at ambient 25 C at 50% humidity; (b) a compressionstrength of at least about 1500, 2000, 3000, 10,000 psi according toASTM C873 with a 0.01 inch/min of cross-head speed at ambient 25 C at50% humidity; (c) a flex strength of at least about 500 psi, 750, 1000according to ASTM C873 with a 0.01 inch/min of cross-head speed atambient 25 C at 50% humidity; (e) a fracture toughness of at least about0.3 Mpa root meter, pref. 0.6, 08 according to ASTM C1421; (f) a ratioof tensile strength to compressive strength of at least about 10, 15%,20, and 30 wherein the tensile strength is measured according to ASTMC1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50%humidity and the compression strength is measured according to ASTM 873with a 0.01 inch/min of cross-head speed at ambient 25 C at 50%humidity; and (g) a flex fatigue resistance such that the curedcomposition can be subjected to a stress of 50% of the curedcomposition's ultimate failure strength for at least 1000 cycles withoutbreaking.

In another embodiment, the invention relates to a compositioncomprising: (1) from about 10 to about 25 weight percent of athermosetting resin based on the total weight of the composition; (2)from about 15 to about 25 weight percent of a microscopic filler basedon the total weight of the composition; (3) from about 30 to about 70weight percent of an aggregate based on the total weight of thecomposition; and (4) an intercalatable nanoclay, an exfoliatablenanoclay, or a mixture thereof.

In yet another embodiment, the instant invention relates to a method ofcementing a subterranean formation. The method comprises pumping asuspension comprising (1) from about 15 to about 25 weight percent basedon the total weight of the suspension of a first component selected fromthe group consisting of calcium carbonate, talc, silica, and mixturesthereof; (2) from about 30 to about 70 weight percent based on the totalweight of the suspension of a second component selected from the groupconsisting of crushed rock, gravel, sand and mixtures thereof; (3) fromabout 10 to about 25 weight percent based on the total weight of thesuspension of a thermosetting resin; and (4) a catalyst capable causingthe suspension to cure. The cured composition is characterized by aratio of tensile strength to compressive strength of at least about 20wherein the tensile strength is measured according to ASTM C1273 with a0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity andthe compression strength is measured according to ASTM 873 with a 0.01inch/min of cross-head speed at ambient 25 C at 50% humidity.

DETAILED DESCRIPTION OF THE INVENTION General Process and Composition

The instant invention pertains in one embodiment to a method ofcementing a well or other subterranean formation in, for example, oiland gas operations. The precise method and composition employed willvary depending upon a number of factors. Such factors include, forexample, the nature and type of well, the depth, the fluids beingemployed and/or produced, pressures, temperatures, desired set times,available equipment, etc.

Generally, the methods employed will usually comprise a step of placinga suspension at a desired location by, for example, pumping thesuspension and then allowing it to cure. The particular manner ofpumping is not critical so long as the suspension is able to be pumpedto the desired location. Such desired location may vary by well orapplication but is often an annular area that occurs between an innerdiameter of a wellbore and an outer diameter of the casing. This may beaccomplished in any convenient manner and usually introducing thesuspension at a ground surface into an upper end of casing such that thesuspension flows through to the bottom of the casing where it exits andthen flows up an annulus. In this manner the suspension may be placedbetween the pipe and the walls of a well bore. Typical pumps and othermethods generally used for conventional primary cementing applicationsmay sometimes be employed in this step. General cementing methods andoperations are described in, for example, U.S. Pat. Nos. 7,748,455;7,757,765; 7,798,225; and 8,124,569 which are incorporated herein byreference to the extent that they are not inconsistent with the instantspecification.

Suitable suspensions typically comprise (1) a filler mixture and (2) atleast about 5 weight percent of a thermosetting resin based on the totalweight of resin and filler mixture. By thermosetting resin is meantthose resins which are usually capable of undergoing an irreversiblephase transformation after, for example, curing. Advantageously, thesuspension may be made to cure when subjected to a catalyst and usuallymay not require substantial amounts of Portland cement and the like as abinder or otherwise. This is useful in that the composition may lacksubstantial amounts of water and/or hexavalent chromium compounds. Insome embodiments the suspension is substantially free of water,hexavalent chromium compounds, or both. In addition, unlike traditionalcementing compositions, the compositions employed herein give off verylittle or no greenhouse gases like carbon dioxide during the settingprocess.

The cured composition often comprises one or more, two or more, three ormore, four or more, five or more, six or more, or all of a number ofuseful characteristics.

Useful characteristics may include, for example,

(a) a tensile strength of at least about 300, or at least about 1000, orat least about 1500 psi according to ASTM C1273 with a 0.01 inch/min ofcross-head speed at ambient 25 C at 50% humidity;

(b) a compression strength of at least about 1500, or at least about2000, or at least about 3000, or at least about 10,000 psi according toASTM C873 with a 0.01 inch/min of cross-head speed at ambient 25 C at50% humidity;

(c) a flex strength of at least about 500, or at least about 750, or atleast about 1000 psi according to ASTM C873 with a 0.01 inch/min ofcross-head speed at ambient 25 C at 50% humidity;

(e) a fracture toughness of at least about 0.3, or at least about 0.6,or at least about 0.8 Mpa root meter according to ASTM C1421;

(f) a ratio of tensile strength to compressive strength of at leastabout 10, or at least about 15, or at least about 20, or at least about30 wherein the tensile strength is measured according to ASTM C1273 witha 0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity andthe compression strength is measured according to ASTM 873 with a 0.01inch/min of cross-head speed at ambient 25 C at 50% humidity; and/or

(g) a flex fatigue resistance such that the cured composition can besubjected to a stress of 50% of the cured composition's ultimate failurestrength for at least 1000, or at least 1500, or at least 2000 cycleswithout breaking.

Filler Mixture

The type and amount of filler mixture employed in the pumpablesuspension may vary widely depending upon the thermosetting resinemployed, as well as, the desired characteristics of the suspension andcured composition. Generally, the filler mixture may comprise an organicmaterial, an inorganic material, or a mixture thereof. Typical materialsthat may be useful in the filler mixture include, for example, materialsselected from the group consisting of calcium carbonate, kaolin, talc,silica, rock, gravel, sand, minerals, allotropic carbon, silicates,metallics, and mixtures thereof.

The amount of filler mixture in the suspension varies depending upon theother ingredients, desired application, and/or desired performance.Generally, the amount of filler mixture, i.e., non-thermosetting resin,in the suspension is usually at least about 50, or at least about 70, orat least about 95 weight percent based on the total weight of thesuspension. On the other hand, the amount of filler mixture in thesuspension is usually less than about 96, or less than about 90, or lessthan about 80 weight percent based on the total weight of thesuspension. Similarly, the size of the component(s) in the fillermixture may vary widely and can be microscopic, macroscopic, ornanoscopic.

In some instances it may be useful to employ a mixture of two differentcomponents as the filler mixture. For example, the filler mixture maycomprise a first component selected from the group consisting of calciumcarbonate, talc, silica, and mixtures thereof and a second componentselected from the group consisting of crushed rock, gravel, sand andmixtures thereof. In such instances, the first component may comprise atleast about 10, or at least about 15 weight percent up to about 35, orup to about 25 weight percent wherein the weight percents are based onthe total weight of resin and filler mixture. Similarly, the secondcomponent may comprise at least about 20, or at least about 30 weightpercent up to about 80, or up to about 70 weight percent wherein theweight percents are based on the total weight of resin and fillermixture.

The particle size distribution of the first or second component isusually not critical so long as there is a homogeneous distribution Theparticle size distribution may be used to assist in controlling, forexample, the rheological properties of the suspension. In particular, ifemploying the first and second components above, then the particle sizedistribution of the first component may be selected for desiredproperties. In this vein, a particle size distribution for the firstcomponent of at least about 0.5, or at least about 1, or at least about5 micron up to about 50, or up to about 25, or up to about 10, or even100 microns based on laser scattering may often prove beneficial.

Thermosetting Resin, Catalyst and Curing

Generally, the thermosetting resin is mixed with the filler mixture inany convenient manner and in any convenient order. Heating is notusually necessary but may be useful in some cases to increase theviscosity of the resin and augment the mixing process. Thus, thetemperature during mixing is usually from about 70 to about 200° F. Suchheating, when employed, is usually done in any convenient manner such asby conduction or convection heating. In some instances to facilitate themixing process it may be useful to add the components of the fillermixture to the resin in order of increasing particle size. This mayfacilitate wetting and speed the mixing process.

The resin(s) and amount will vary depending upon the other ingredients,the desired applications, and properties. Generally, any resin that iscapable of being pumped to or placed in the desired location and settingmay prove useful. For example, typical thermosetting resins may beemployed and may be selected from the group consisting of an epoxyresin, a polyester resin, a vinyl ester resin, a polyurethane resin, acarboxylic based resin, a phenolic based resin, a furan based resin, across-linked thermoplastic resin, an epoxy novolac, a cellulose basedresin like rayon, and mixtures thereof. Generally, thermosetting resinsuseful in the present invention include those with gel times rangingfrom as little as 10 minutes to as many as 10 hours which gel times maybe varied depending upon a particular catalyst(s), i.e., initiator(s),employed. Of course, these times may also advantageously be adjusted byuse of promoters, inhibitors, and temperature adjustment.

Particularly preferred thermosetting resins include those that provideappropriate cost, mechanical properties, and processability for a givenapplication. Generally, epoxy resins by themselves without anappropriate filler mixture and amount may prove inadequate for manyapplications. On the other hand, vinyl ester and polyester thermosettingresins may prove very useful in a number of cementing compositionapplications due to their low cost and often low viscosity. That is,preferred vinyl ester resins and preferred polyester resins may have aviscosity of at least about 100, or at least about 120 up to about 5000,or up to about 500 centipoise as measured on a Brookfield viscometer at60 rpm/60 seconds at 25° C. Such resins may be highly cross-linked suchas cross-linked terephthalic based polyester resins or cross-linkedisophthalic polyester resins or crosslinked orthophthalic polyesterresins or crosslinked cycloaliphatic based polyester resins. Typically,other components in these resins may include, for example, maleicanhydride and a glycol and a crosslinking agent like styrene or anacrylic.

Another particularly useful resin may include a polyester resin with orwithout styrene or an acrylic cross-linking agent. Should styrene bedesired usual amounts may include from at least about 25%, or at leastabout 35% up to about 40%, or up to about 50%.

Other preferred thermosetting resins include, for example, epoxy resinssuch as the D.E.R.™ line of epoxy resins available from The Dow ChemicalCompany. Such resins include D.E.R.™ 331™ (CAS No.25085-99-8/(25068-38-6)) which CAS information and D.E.R. “331”specification sheet are incorporated by reference herein. Such epoxyresins are often liquid reaction products of epichlorohydrin andbisphenol A that may be cured at ambient conditions or elevatedtemperatures with a variety of curing agents such as aliphaticpolyamines, polyamides, amidoamines, cycloaliphatic amines. In someinstances, curing thermosetting resins such as these and others at anelevated temperature may improve chemical resistance, glass transitiontemperature, or other properties.

References such as Plastics Materials by J. A. Brydson published byButterworth-Heinemann (ISBN-10: 0750641320 and ISBN-13: 978-0750641326)and Introduction to Polymer Science by V. R. Gowarikar, N. V.Vishwanathan, Jayadev Sreedhar published by New Age International PvtLtd Publishers (ISBN-10: 0852263074 and ISBN-13: 978-0852263075) may beuseful in selecting a specific class of thermosetting resins for aparticular desired application and are incorporated by reference hereinto the extent that they are not inconsistent with the instantspecification.

The amount of thermosetting resin employed varies by type of resin,other components, and the desired application. Generally, the amount ofthermosetting resin is at least about 5, or at least about 10, or atleast about 13 weight percent based on the total weight of resin andfiller mixture. On the other hand, generally the amount of thermosettingresin is usually less than about 35, or less than about 25, or less thanabout 17 weight percent based on the total weight of resin and fillermixture.

The catalyst selected should be selected based upon the thermosettingresin and desired curing characteristics. Suitable catalysts includethose typically used with thermosetting resins such as heat or time, aswell as, chemical catalysts such as peroxide, amines, anhydrides,phenolics, halides, oxides and many others may be useful in selecting aspecific class of thermosetting resins for a particular desiredapplication. Such catalysts and use in thermosetting resins aredescribed in detail in references such as Plastics Materials by J. A.Brydson published by Butterworth-Heinemann (ISBN-10: 0750641320 andISBN-13: 978-0750641326) and Introduction to Polymer Science by V. R.Gowarikar, N. V. Vishwanathan, Jayadev Sreedhar published by New AgeInternational Pvt Ltd Publishers (ISBN-10: 0852263074 and ISBN-13:978-0852263075) which are incorporated by reference herein to the extentthat they are not inconsistent with the instant specification.

The catalyst may be mixed with the suspension in any convenient mannerto cause the desired curing to begin and may vary depending upon theapplication. That is, the catalyst may be mixed with the suspensionprior to, simultaneously with, or subsequent to pumping of thesuspension. In a particularly preferable embodiment, the catalyst ismaintained on-site and mixed into the suspension immediately beforepumping.

If desired, a catalyst “kicker” or accelerator may be employed as knownin the art. The may be employed prior to, simultaneously with, orsubsequent to any catalyst addition in any convenient manner.

Density Control

The density of the suspension should preferably be suitable for pumpingthe suspension to the desired location which may involve, for example,displacing well fluid. Accordingly, the control of the density of thesuspension may prove useful for some applications. Typical densities ofthe formulations described herein are usually from about 6 lb/gal toabout 30 lb/gal.

Advantageously, density of the suspensions described herein may often becontrolled in a number of ways. For example, the ratios of variouscomponents of varying densities may be varied. Alternatively, variousadditives may be employed such as, for example, beads made of glass orother materials, closed cell foam or other cellular structures,microspheres made of glass, polymers, silicates, etc., higher densitymaterials than that of the suspension, and/or nitrogen or othertraditional foaming methods to reduce density.

Control of Mechanical Properties

The mechanical properties of the cured composition may be controlled viaa number of different mechanisms that will become apparent to theskilled artisan with the benefit of the instant specification and withroutine experimentation. For example, the tensile strength and/orcompression strength and/or flex strength may be conveniently controlledby, for example, with the choice of thermosetting resin. That is, shouldone desire to modify the tensile strength and/or compression strengthand/or flex strength then one may alter the type or amount ofthermosetting resin. Generally, epoxy resins give higher tensile,compression and flex strength than vinyl ester resins which give highertensile, compression, and flex strength than polyester resins. Thus, thetensile, compression, and/or flex strength may be modified by employingmore or less of the various resins as desired.

Advantageously, flex strength may also be readily controlled in manycompositions via control of the type and amount of thermosetting resinor resins employed. For example, if higher flex strength is necessaryfor a thermosetting resin such as a polyester resin then one mayincrease the aromatic content of the polymer backbone. That is, one maychange maleic anhydride to, for example, phthalic anhydride and/orincrease the ratio of maleic anhydride to phthalic anhydride. Higherflex strength may also be obtained by, for example, using additives thataugment the binding between thermosetting resin and any filler and/orfiber components.

Similarly, compression strength may be increased by a number of methods.For example, if one desires a higher compression strength then a highermodulus resin such as an epoxy resin may be employed. Alternatively oradditionally, raising the amount of filler content may also increase thecompression strength in some instances.

The glass transition temperature, Tg, may also be controlled via thetype and amount of thermosetting resin. For example, to raise the glasstransition temperature of a given composition one may add or increasethe amount of vinyl ester resin relative to any polyester resin. In thismanner, one may sometimes adjust the Tg upward by as much as 20-40° C.

Advantageously, the fracture toughness and/or resistance to crackpropagation may also be controlled. One way of doing so is by theaddition or introduction of reactive diluents such as rubbers (e.g.,isoprene, butadiene) onto the thermosetting resin backbone. This oftenwill increase the fracture toughness and/or resistance to crackpropagation of the cured compositions. Alternatively or additionally,the blending of rubbers or other highly tough materials into thesuspension may assist in a similar manner.

Additives

Other additives may be employed in various amounts as may be useful ordesired so long as they do not substantially interfere with desiredcharacteristics for a given application. Such additives may includethose that assist with rheological properties, density, curing,emulsifying, pH control, dispersing, wetting, environmental resistance,chemical resistance, hardness, stabilizers, and modifiers for abrasionresistance and the like.

A particularly useful additive may be fibers. The addition of fiber maybe used to increase tensile and flex strength of the compositions. Thetype and amount of fiber addition may vary depending upon the othercomponents and how much tensile or flex strength is desired. Typically,the addition of such fibers comprised of glass, carbon, Kevlar,polymers, or inorganic minerals like basalt, etc. may be useful. Theseadded fibers may take any form, for example, chopped, continuous, woven,etc. Typical amounts of added fibers may be at least about 0.5, or atleast about 4, or at least about 10 up to about 20, or up to about 45weight percent based on the total weight of the composition.

Intercalatable or Exfoliatable Nanoclay Compositions

The present invention also pertains to novel compositions which may beuseful for downhole cementing operations, as well as, a host of otherapplication such as above and below ground civil structures, miningstructures, decking, paving, roofing, utility enclosures, manholes,below ground pre-cast structures, etc. The composition is similar to thepreviously mentioned composition above wherein an improvement comprisesadding an intercalatable nanoclay, an exfoliatable nanoclay, or amixture thereof. The nanoclay may assist in adding toughness to thecomposition such that a cured composition exhibits less crackpropagation when subjected to stress. While not wishing to be bound toany particular theory it is believed that when the nanoclay isintercalated via ultrasound or other means, then the path of any crackbecomes more tortuous such that it is less linear.

Typical compositions containing nanoclay may comprise a thermosettingresin, a microscopic filler, an aggregate, and an intercalatable and/orexfoliatable nanoclay. The amounts of each may vary depending upon theapplication. Generally, useful compositions may comprise:

-   (1) from about 10 or from about 13 up to about 17 or up to about 25    weight percent of a thermosetting resin based on the total weight of    the composition;-   (2) from about 15 to about 25 weight percent of a microscopic filler    based on the total weight of the composition;-   (3) from about 30 to about 70 weight percent of an aggregate based    on the total weight of the composition; and-   (4) an intercalatable nanoclay, an exfoliatable nanoclay, or a    mixture thereof.

The amount and type of nanoclay employed, of course, depends on theother components and desired characteristics. However, in some instancesthe nanoclay may comprises from about 0.5 to about 2 weight percentbased on the total weight of the composition. Suitable nanoclaysinclude, for example, montmorillonite, bentonite, various silicates,quartzes and other mineral compounds. As described above, a catalyst isusually employed to begin the curing process. Those catalysts describedabove may be employed so long as they do not significantly interferewith intercalation and/or substantially degrade the nanoclay.

Unless specifically defined otherwise, all technical or scientific termsused herein have the same meaning as commonly understood by one ofordinary skill in the art to which this invention belongs. Although anymethods and materials similar or equivalent to those described hereincan be used in the practice or testing of the present invention, thepreferred methods and materials are better illustrated by the use of thefollowing non-limiting examples, which are offered by way ofillustration and not by way of limitation.

EXAMPLES

The following examples are presented to further illustrate and explainthe claimed subject matter and should not be taken as limiting in anyregard. All weight percentages are based on the total composition unlessstated otherwise and all mixing is conducted at ambient temperaturesunless stated otherwise.

Example 1

41% by weight of an unsaturated polyester resin is mixed with 41% byweight of calcium carbonate with a particle size distribution rangingfrom 5 to 20 microns and 18 percent by weight of chopped glass fiber.The mixture is stirred until it appears to be a substantiallyhomogeneous suspension. The suspension can then be mixed with a curingagent such as benzoyl peroxide or methyl ethyl ketone peroxide andpumped or placed in a desired location such as an annulus of a wellbore.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Density of 1.3 to 1.7 gm/cc; Tensile Strength of 1000-5000 psi; Flexstrength of 5000-10000 psi; Compressive strength in the range of7000-20000 psi; a fracture toughness of 0.2 to 1.3 MPa root meter; and aglass transition temperature of 60 to 150° C.

Example 2

In a similar manner as Example 1, 15% by weight of an unsaturatedpolyester resin is mixed with 30% sand (#12 and #20), 35% of #5 gravel,and 20% of CaCO3 to form a substantially homogeneous suspension. Thesuspension can then be mixed with a curing agent such as benzoylperoxide or methyl ethyl ketone peroxide and pumped or placed in adesired location such as an annulus of a wellbore.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Tensile strength of 1000-1400 psi; Compressive Strength of 8000-22000psi; Flex strength of 2000-8000 psi; Density of 2.2-2.5 gm/cc; glasstransition temp of about 60-150 C; and a fracture toughness of 0.3 to0.6 MPa root meter.

Example 3

Example 1 is repeated except that 10-30% by weight of glass beads ormicrospheres are substituted for an equal portion of the resin andfiller.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Tensile strength of 1000-3000 psi; Compressive Strength of 6000-20000psi; Flex strength of 2000-8000 psi; Density of 0.7-1.3 gm/cc; glasstransition temp of about 60-150 C; and a fracture toughness of 0.3 to0.6 MPa root meter.

Example 4

Example 2 is repeated except that about 2% by weight of chopped fiber(glass, carbon, basalt, etc) are substituted for an equal portion of theresin and filler.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Tensile strength of 1000-3000 psi; Compressive Strength of 8000-22000psi; Flex strength of 2500-9500 psi; Density of 0.7-1.3 gm/cc; glasstransition temp of about 60-150 C; and a fracture toughness of 0.3 to0.6 MPa root meter.

Example 5

Example 2 is repeated except that 30% by weight epoxy resin and 15% byweight of sand are employed instead of the polyester and gravel andmixing is conducted at from 150-200 F.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Tensile strength of 3000-6000 psi; Compressive Strength of 5000-25000psi; Flex strength of 3000-11000 psi; Density of 0.7-1.3 gm/cc; glasstransition temp of about 100-400 C; and a fracture toughness of 0.6 to1.5 MPa root meter.

Example 6

Example 2 is repeated except that additional sand is employed instead ofgravel.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Tensile strength of 1000-1400 psi; Compressive Strength of 8000-22000psi; Flex strength of 2000-8000 psi; Density of 2.2-2.5 gm/cc; glasstransition temp of about 60-150 C; and a fracture toughness of 0.3 to0.6 MPa root meter.

Example 7

Example 2 is repeated except that vinyl ester resin is employed in placeof polyester resin.

Depending upon resin chemistry and particle size distribution the curedcompositions may yield the following range of properties using the ASTMtesting methods described above:

Tensile strength of 1000-2500psi; Compressive Strength of 8000-22000psi; Flex strength of 3000-8000 psi; Density of 2.2-2.5 gm/cc; glasstransition temp of about 80-125 C; and a fracture toughness of 0.2 to1.2 MPa root meter.

The claimed subject matter is not to be limited in scope by the specificembodiments described herein. Indeed, various modifications of theinvention in addition to those described herein will become apparent tothose skilled in the art from the foregoing description. Suchmodifications are intended to fall within the scope of the appendedclaims.

All references cited herein are incorporated herein by reference intheir entirety to the extent that they are not inconsistent and for allpurposes to the same extent as if each individual publication, patent orpatent application was specifically and individually indicated to beincorporated by reference in its entirety for all purposes.

The citation of any publication is for its disclosure prior to thefiling date and should not be construed as an admission that the presentinvention is not entitled to antedate such publication by virtue ofprior invention.

1. A suspension comprising: (1) from about 15 to about 25 weight percentbased on the total weight of the suspension of a first componentselected from the group consisting of calcium carbonate, talc, silica,and mixtures thereof wherein the first component has an average particlesize distribution of from about 0.5 microns to about 100 microns basedon laser scattering; (2) from about 30 to about 70 weight percent basedon the total weight of the suspension of a second component selectedfrom the group consisting of crushed rock, gravel, sand and mixturesthereof wherein the second component has an average particle sizedistribution of from about 50 microns to about 600 microns based onlaser scattering; (3) from about 25 to about 45 weight percent based onthe total weight of the suspension of a thermosetting resin selectedfrom a polyester resin, a vinyl ester resin, and mixtures thereof; and(4) a catalyst capable of causing the suspension to gel and cure andwherein said gel time is from about 2 to about 10 hours; wherein theuncured suspension has a pumpability of from about 10 to about 120Bearden units and wherein the cured composition is characterized by aratio of tensile strength to compressive strength of at least about 10%wherein the tensile strength is measured according to ASTM C1273 with a0.01 inch/min of cross-head speed at ambient 25 C at 50% humidity andthe compression strength is measured according to ASTM 873 with a 0.01inch/min of cross-head speed at ambient 25 C at 50% humidity.
 2. Thesuspension of claim 1 wherein the resin has a viscosity of from about100 to about 5000 centipoise as measured on a Brookfield viscometer at60 rpm/60 seconds at 25° C.
 3. The suspension of claim 1 wherein thecatalyst is selected from the group consisting of peroxides, amines,anhydrides, phenolics, halides, oxides, and mixtures thereof.
 4. Thesuspension of claim 1 wherein the cured composition comprises three ormore or more of the following characteristics: (a) a tensile strength ofat least about 300 psi according to ASTM C1273 with a 0.01 inch/min ofcross-head speed at ambient 25 C at 50% humidity; (b) a compressionstrength of at least about 1500 psi according to ASTM C873 with a 0.01inch/min of cross-head speed at ambient 25 C at 50% humidity; (c) a flexstrength of at least about 500 psi according to ASTM C873 with a 0.01inch/min of cross-head speed at ambient 25 C at 50% humidity; (d) afracture toughness of at least about 0.3 Mpa root meter according toASTM C1421; (e) a ratio of tensile strength to compressive strength ofat least about 10% wherein the tensile strength is measured according toASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at50% humidity and the compression strength is measured according to ASTM873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50%humidity; and (f) a flex fatigue resistance such that the curedcomposition can be subjected to a stress of 50% of the curedcomposition's ultimate failure strength for at least 1000 cycles withoutbreaking.
 5. A method of cementing a subterranean formation comprisingthe step of pumping a suspension comprising: (1) from about 15 to about25 weight percent based on the total weight of the suspension of a firstcomponent selected from the group consisting of calcium carbonate, talc,silica, and mixtures thereof; (2) from about 30 to about 70 weightpercent based on the total weight of the suspension of a secondcomponent selected from the group consisting of crushed rock, gravel,sand and mixtures thereof; (3) from about 20 to about 40 weight percentbased on the total weight of the suspension of a thermosetting resin;and (4) a catalyst capable causing the suspension to cure; wherein thecured composition is characterized by a ratio of tensile strength tocompressive strength of at least about 10% wherein the tensile strengthis measured according to ASTM C1273 with a 0.01 inch/min of cross-headspeed at ambient 25 C at 50% humidity and the compression strength ismeasured according to ASTM 873 with a 0.01 inch/min of cross-head speedat ambient 25 C at 50% humidity.
 6. The method of claim 5 wherein thethermosetting resin is selected from the group consisting of an epoxyresin, a polyester resin, a vinyl ester resin, a polyurethane resin, acarboxylic based resin, a phenolic based resin, a cross-linkedthermoplastic resin, an epoxy novolac, a cellulose based resin, andmixtures thereof.
 7. The method of claim 5 wherein the thermosettingresin is selected from the group consisting of a polyester resin, avinyl ester resin, and mixtures thereof
 8. The method of claim 5 whereinthe first component has a particle size distribution of from about 0.5microns to about 100 microns based on laser scattering.
 9. A method ofcementing a subterranean formation comprising the step of pumping asuspension comprising: (1) from about 15 to about 25 weight percentbased on the total weight of the suspension of a first componentselected from the group consisting of calcium carbonate, talc, silica,and mixtures thereof; (2) from about 30 to about 70 weight percent basedon the total weight of the suspension of a second component selectedfrom the group consisting of crushed rock, gravel, sand and mixturesthereof; (3) from about 10 to about 25 weight percent based on the totalweight of the suspension of a thermosetting resin; and (4) a catalystcapable causing the suspension to cure; wherein the cured composition ischaracterized by a ratio of tensile strength to compressive strength ofat least about 10% wherein the tensile strength is measured according toASTM C1273 with a 0.01 inch/min of cross-head speed at ambient 25 C at50% humidity and the compression strength is measured according to ASTM873 with a 0.01 inch/min of cross-head speed at ambient 25 C at 50%humidity.
 10. The method of claim 9 wherein the thermosetting resin isselected from the group consisting of an epoxy resin, a polyester resin,a vinyl ester resin, a polyurethane resin, a carboxylic based resin, aphenolic based resin, a cross-linked thermoplastic resin, an epoxynovolac, a cellulose based resin, and mixtures thereof.
 11. The methodof claim 9 wherein the thermosetting resin is selected from the groupconsisting of a polyester resin, a vinyl ester resin, and mixturesthereof
 12. The method of claim 9 wherein the first component has aparticle size distribution of from about 0.5 microns to about 100microns based on laser scattering.
 13. The method of claim 9 wherein thecatalyst is mixed with the suspension prior to, simultaneously with, orsubsequent to pumping.
 14. The method of claim 9 wherein the catalyst ismixed with the suspension prior to pumping.
 15. The method of claim 9,further comprising the step of drilling the well and running a casing,wherein the step of cementing applies to cement the casing.
 16. Themethod of claim 9 wherein the suspension comprises substantially nohexavalent chromium compounds.
 17. The method of claim 9 wherein thesuspension comprises substantially no water.